A hard-disk drive (HDD) is a non-volatile storage device that is housed in a protective enclosure and stores digitally encoded data on one or more circular disk having magnetic surfaces. When an HDD is in operation, each magnetic-recording disk is rapidly rotated by a spindle system. Data is read from and written to a magnetic-recording disk using a read/write head that is positioned over a specific location of a disk by an actuator. A read/write head uses a magnetic field to read data from and write data to the surface of a magnetic-recording disk. Write heads make use of the electricity flowing through a coil, which produces a magnetic field. Electrical pulses are sent to the write head, with different patterns of positive and negative currents. The current in the coil of the write head induces a magnetic field across the gap between the head and the magnetic disk, which in turn magnetizes a small area on the recording medium.
Some HDDs employ a stainless steel cover, in conjunction with a base, to form the HDD enclosure. Steel is composed primarily of iron with some amount of carbon. Thus, stainless steel is a steel alloy composed of steel, i.e., iron, with a certain amount of chromium. Stainless steel does not readily corrode and oxidize (i.e., rust), as compared to ordinary steel, and therefore is often a reasonable choice for an HDD cover. However, stainless steel is not corrosion-proof or rust-proof and thus there is a phenomenon in HDD technology referred to as “Fe smear” or “iron smear”. With Fe smear, iron contamination migrates from the cover, for example, to the slider and/or disk which in turn can causes weak write operations. Weak write operations are at some degree considered an HDD failure, which has a direct effect on the reliability of the drive. Therefore, there are challenges associated with inhibiting Fe smear in HDDs.
Any approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.